diff --git a/sys/kern/subr_sbuf.c b/sys/kern/subr_sbuf.c
index 20a831aa75b..66822115dbc 100644
--- a/sys/kern/subr_sbuf.c
+++ b/sys/kern/subr_sbuf.c
@@ -383,7 +383,7 @@ sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
 /*
  * Call the drain and process the return.
  */
-static int
+int
 sbuf_drain(struct sbuf *s)
 {
 	int len;
diff --git a/sys/sys/sbuf.h b/sys/sys/sbuf.h
index 10b59f360cd..d87e3917b84 100644
--- a/sys/sys/sbuf.h
+++ b/sys/sys/sbuf.h
@@ -95,6 +95,7 @@ int		 sbuf_vprintf(struct sbuf *, const char *, __va_list)
 int		 sbuf_nl_terminate(struct sbuf *);
 int		 sbuf_putc(struct sbuf *, int);
 void		 sbuf_set_drain(struct sbuf *, sbuf_drain_func *, void *);
+int		 sbuf_drain(struct sbuf *);
 int		 sbuf_trim(struct sbuf *);
 int		 sbuf_error(const struct sbuf *);
 int		 sbuf_finish(struct sbuf *);